Bronchoalveolar lavage specimens are usually split between cytology and microbiology. As different methodologies are used by these two laboratories in the work-up of these specimens, we thought it would be useful to review the results obtained on these specimens by each laboratory. Such a review might help define the relative sensitivities of the different procedures employed, suggest areas of redundancy that might be candidates for elimination, and help identify the procedures most likely to produce clinically significant results. Preliminary results of the data analyzed thus far suggest that cytology preparations are more sensitive for the direct detection of significant fungal pathogens than the smears prepared in microbiology, presumably because of the larger volume of material used for preparation of smears in cytology. More data will need to be analyzed before any conclusions can be reached on the relative sensitivities of the procedures performed in the two laboratories for the detection of other pathogens such as Mycobacterium tuberculosis and Pneumocystis carinii.